               (dom/img #js {:src (u/lesson-thumbnail-url lesson) :key "img"})
               (dom/p #js {:key "p"} title))))))
 
-(def lesson-cell (om/factory LessonCell))
+(def lesson-cell (om/factory LessonCell {:keyfn :db/id}))
 
 (om/defui ^:once TopicSideBarLink
   static om/IQuery

    (let [{:keys [topic/lessons]} (om/props this)
          lesson-groups (partition 6 6 nil lessons)]
      (dom/div #js {:className "thumbnails"}
        (for [lessons lesson-groups]
          (dom/div #js {:className "row" :style #js {:margin "0 0 20px 0"}}
            (map lesson-cell lessons)))))))

(def home-course-topic-open (om/factory HomeCourseTopicOpen {:keyfn :db/id}))


(om/defui ^:once LessonCell
  static om/IQuery
  (query [_] [:db/id :lesson/title :youtube/id :lesson/type :url/slug])

  static om/Ident
  (ident [_ props] (u/model-ident props))
